CVE-2026-5503
out-of-bounds write in TLSX_EchChangeSNI via attacker-controlled publicName
- State
- Published
- Severity
- 6.9 Medium
- Published
- Apr 9, 2026
- Updated
- Apr 10, 2026
- Reserved
- Apr 3, 2026
Description
In TLSX_EchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSX_Find returned NULL. This caused TLSX_UseSNI to attach the attacker-controlled publicName to the shared WOLFSSL_CTX when no inner SNI was configured. TLSX_EchRestoreSNI then failed to clean it up because its removal was gated on serverNameX != NULL. The inner ClientHello was sized before the pollution but written after it, causing TLSX_SNI_Write to memcpy 255 bytes past the allocation boundary.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N | wolfSSL |
Weaknesses
- CWE-787 Out-of-bounds write
Affected Products
| Product | Versions |
|---|---|
wolfSSLwolfSSL |
|
References
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